Semiconductor device and data processing system selectively operating as one of a big endian or little endian system

ABSTRACT

The present invention is to provide a semiconductor device that can correctly switch endians on the outside even if the endian of a parallel interface is not recognized on the outside. The semiconductor device includes a switching circuit and a first register. The switching circuit switches between whether a parallel interface with the outside is to be used as a big endian or a little endian. A first register holds control data of the switching circuit. The switching circuit regards the parallel interface as the little endian when first predetermined control information, that is unchanged in the values of specific bit positions even if its high-order and low-order bit positions are transposed, is supplied to the first register, and regards the parallel interface as the big endian when second predetermined control information, that is unchanged in the values of specific bit positions even if its high-order and low-order bit positions are transposed, is supplied to the first register. Whatever the endian setting status, the control information can be correctly inputted without being influenced by the endian setting status.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese patent applicationNo. 2005-160901 filed on Jun. 1, 2005, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

The present invention relates to a technology for switching betweenwhether a parallel interface is to be used as a big endian or a littleendian. More particularly, the present invention relates to asemiconductor device used as a peripheral device such as a transferslave, and a data processing system which includes a host device such asa transfer master, and a peripheral device such as a transfer slave.

In the case where a parallel interface is performed between a hostdevice and a peripheral device (that is, between a transfer master and atransfer slave, or between a bus master and a bus slave), when thetransfer unit of data to be transferred exceeds the number of parallelbits (bus width) of a data bus, the data must be transferred in aplurality of batches. Transfer modes in this case include a big endianand a little endian. In a big endian mode, high-order bytes andlow-order bytes of the data are transferred in that order. In a littleendian mode, low-order bytes and high-order bytes of the data aretransferred in that order. Therefore, the transfer modes must matchbetween the host device and the peripheral device. If the host devicetransfers data in the big endian mode and the peripheral device receivesit in the little endian mode, high-order bytes and low-order bytes ofthe data received by the peripheral device would be reversed with thedata transferred by the host device.

Conventionally, semiconductor devices such as peripheral devices haveenabled switching between a big endian and a little endian by pull-up orpull-down of external terminals. However, this would require an extramode terminal for endian switching.

A technology for automatic switching of endians is disclosed in PatentDocument 1. According to it, an endian conversion information part thatholds an address value to be subjected to endian switching, and adetermination part that automatically determines whether to performendian switching by comparing address values are provided to enableautomatic execution of endian switching.

-   Japanese Unexamined Patent Publication No. Hei 8 (1996)-305628

SUMMARY OF THE INVENTION

However, also in the technology for automatic switching of endians, as aprecondition, host devices such as a transfer master and a bus mastermust recognize in advance the endians of peripheral devices such as atransfer slave and a bus slave. Otherwise, information itself for endianswitching cannot be correctly received in the peripheral devices.Accordingly, there occur cases where the host devices must perform atransfer operation in line with the endians of the peripheral devices.This means that the peripheral devices stipulate the operation of thehost devices, burdening system design.

An object of the present invention is to provide a semiconductor devicethat can correctly switch endians on the outside even if the endian of aparallel interface is not recognized on the outside.

Another object of the present invention is to provide a data processingsystem that can match the endian of a peripheral device to the endian ofa host device even if the host device does not recognize the endian ofthe peripheral device.

The above-mentioned objects and other objects and novel characteristicsof the present invention will become apparent from the description ofthis specification and the accompanying drawings.

Typical inventions disclosed in the present application will be brieflydescribed below.

[1] A semiconductor device 1 relating to the present invention includesa switching circuit 36 and a first register 10. The switching circuitswitches between whether a parallel interface with the outside is to beused as a big endian or a little endian. A first register holds controldata (CMDDL, CMDDB) of the switching circuit. The switching circuitregards the parallel interface as the little endian when firstpredetermined control information (CMDDL), that is unchanged in thevalues of specific bit positions even if its high-order and low-orderbit positions are transposed, is supplied to the first register. Incontrast to this, the switching circuit regards the parallel interfaceas the big endian when second predetermined control information (CMDDB),that is unchanged in the values of specific bit positions even if itshigh-order and low-order bit positions are transposed, is supplied tothe first register. Thereby, whatever the endian setting status of thesemiconductor device, the control information can be correctly receivedwithout being influenced by the endian setting status. Therefore, evenif the endian of the parallel interface is not recognized on theoutside, the endian can be correctly switched on the outside.

As one concrete configuration of the present invention, thesemiconductor device includes a selecting circuit 12 for selecting thefirst register. When predetermined selection information (CMDAS), thatis unchanged in the values of specific bit positions even if itshigh-order and low-order bit positions are transposed, is supplied, theselecting circuit selects the first register to enable the input of thecontrol data. Like the control information, the selection informationcan also be correctly received without being influenced by the endiansetting status.

As a further concrete configuration of the present invention, thesemiconductor device includes a second register 35 for holding theselection information. When predetermined selection information, that isunchanged in the values of specific bit positions even if its high-orderand low-order bit positions are transposed, is supplied to the secondregister, the selecting circuit selects the first register.

As a further concrete configuration of the present invention,information, that is unchanged in the values of specific bit positionseven if its high-order and low-order bit positions are transposed, isinformation the values of high-order bits and low-order bits of whichmatch each other. In the case of 16-bit data, selection information ish0606, first control information is h0101, and second controlinformation is h0000. The symbol h denotes that following digits arehexadecimal.

As a further concrete configuration of the present invention, thesemiconductor device includes a plurality of external terminals (DB7-0)used for the parallel interface with the selection information and thecontrol data. The selection information and the control data areinputted in series using predetermined packets from the externalterminals.

[2] The semiconductor device according to another aspect includes afirst register 10, a second register 35, a selecting circuit 12, and aswitching circuit 36. The first register holds control data forcontrolling whether a parallel interface with the outside is to be usedas a big endian or a little endian. The second register holds selectioninformation (CMDAS) for selecting the control register. The selectingcircuit selects the first register when predetermined selectioninformation the values of high-order bits and low-order bits of whichmatch each other is supplied to the second register. The switchingcircuit regards the parallel interface as the little endian when firstpredetermined selection information (CMDDL) the values of high-orderbits and low-order bits of which match each other is supplied to thefirst register selected by the selecting circuit. In contrast to this,the switching circuit regards the parallel interface as the big endianwhen second predetermined selection information (CMDDB) the values ofhigh-order bits and low-order bits of which match each other is suppliedto the first register selected by the selecting circuit.

Thereby, whatever the endian setting status of the semiconductor device,the control information and the selection information can be correctlyreceived without being influenced by the endian setting status.Therefore, even if the endian of the parallel interface is notrecognized on the outside, the endian can be correctly switched on theoutside.

As one concrete configuration of the present invention, thesemiconductor device includes a plurality of external terminals (DB7-0)used for the parallel interface with the selection information and thecontrol data. The selection information and the control data areinputted in series using predetermined packets from the externalterminals.

As a further concrete configuration of the present invention, theselection information is first command address information given fromthe outside. The first control information is a first command given fromthe outside along with the first command address information. The secondcontrol information is a second command given from the outside alongwith the first command address information.

As a further concrete configuration of the present invention, thesemiconductor device includes a data processing part that performs dataprocessing according to a third command given from the outside alongwith the second command address information.

The data processing part includes a display memory 14 and drivingcircuits 20 and 25 for driving display electrodes of a display on thebasis of display data stored in the display memory. Such a semiconductordevice is a liquid crystal driving control device that is formed on onesemiconductor substrate and controls the display and driving of a liquidcrystal display.

[3] A data processing system according to the present invention includeshost devices 30 and 45, and a peripheral device 1 connected to the hostdevices via a plurality of signal lines. The peripheral device includesa first register that holds control data for controlling whether aparallel interface by the plurality of signals is to be used as a bigendian or a little endian, and a second register that holds selectioninformation for selecting the control register. When selecting the firstregister, the host devices output selection information the values ofhigh-order bits and low-order bits of which match each other to thesecond register. Furthermore, when regarding the parallel interface ofthe peripheral device as the little endian, the host devices outputfirst predetermined information the values of high-order bits andlow-order bits of which match each other to the selected first register.Thereby, the host device can match the endian of the peripheral deviceto its own endian even when not recognizing the endian of the peripheraldevice.

In another data processing system according to the present invention,when regarding the parallel interface of the peripheral device as thebig endian, the host devices output second predetermined controlinformation the values of high-order bits and low-order bits of whichmatch each other to the selected first register. Also in this case, thehost device can match the endian of the peripheral device to its ownendian even when not recognizing the endian of the peripheral device.

As one concrete configuration of the data processing system, theselection information is first command address information outputted bythe host devices. The first control information is a first commandoutputted by the host devices along with the first command addressinformation. The second control information is a second commandoutputted by the host devices along with the first command addressinformation.

As a further concrete configuration, the peripheral device includes adata processing part that performs data processing according to a thirdcommand outputted by the host devices along with the second commandaddress information.

As a further concrete configuration, when the data processing systemincludes a display connected to the peripheral device, the dataprocessing part includes a display memory, and a driving circuit thatdrives display electrodes of the display on the basis of display datastored in the display memory.

As a further concrete configuration, the host devices include amicrocomputer 45B that controls the peripheral device.

As a further concrete configuration, when the data processing systemincludes a high-frequency part connected to the host devices, the hostdevices include a microcomputer 45A that performs baseband processing ofcellular phones.

Effects obtained by typical inventions disclosed in the presentapplication will be briefly described below.

According to the semiconductor device, even if the endian of theparameter interface is not recognized on the outside, endian switchingcan be correctly performed on the outside.

According to the data processing system, even if the host devices do notrecognize the endian of the peripheral device, the endian of theperipheral device can be matched to their own endian.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an example of an endian settingcircuit in a parallel interface circuit;

FIG. 2 is a block diagram showing the construction of a liquid crystaldriving control device according to a semiconductor device;

FIG. 3 is a drawing for explaining signal lines for a parallel interfacein a liquid crystal driving control device;

FIG. 4 is a timing diagram showing operation timing of an endian settingcircuit of FIG. 1;

FIG. 5 is a drawing concisely showing an operation mode of a switchingcircuit in an endian setting circuit;

FIG. 6 is a drawing illustrating command address information CMDAS forselecting an endian setting register, a first endian setting commandCMDDL, and a second endian setting command CMDDB.

FIG. 7 is an address map of a command address register;

FIG. 8 is a block diagram of a cellular phone relating to a dataprocessing system to which a liquid crystal driving control device isapplied;

FIG. 9 is a drawing showing an example of endian setting operations byan MCU; and

FIG. 10 is a drawing for explaining the operation of dynamicallyswitching endian settings when both a baseband processor and anapplication processor control a liquid crystal driving control device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Liquid Crystal Driving ControlDevice

FIG. 2 shows the construction of a liquid crystal driving control device(LCDCNT) 1 as an example of semiconductor device. A host interfacecircuit (HIF) 2 includes a parallel interface circuit (PIF) 3, ahigh-speed serial interface circuit (HSSIO) 4, a low-speed serialinterface circuit (LSSIO) 5, and an output port (OPRT) 6. The parallelinterface circuit (PIF) 3 inputs and outputs information via a parallelbus DB0-7, for example, in units of eight bits in parallel. Thelow-speed serial interface circuit 5 serially inputs and outputs datausing a serial input terminal SDI and a serial output terminal SDO. Thehigh-speed serial interface circuit 4 rapidly inputs and outputs serialdata with amplitude differential using differential data terminals data±and differential strobe terminals stb±. The output port 6 can controllogical levels of output signals of a port terminal OPORT8-0. A chipselect signal CS and a write signal WR are typical strobe signals for aparallel interface. The host interface circuit (HIF) 2, to input andoutput commands and display data to and from a host device (not shown)connected to it, can use the parallel interface circuit 3, thehigh-speed serial interface circuit 4, or the low-speed serial interfacecircuit 5. Which of them is to be used depends on a pull-up or pull-downstate of a mode terminal IM3-0.

The host device transfers commands and data to the host interfacecircuit 2 using a packet of a predetermined format. Although not shownin the drawing, the packet consists of a header part and a body part.The header part includes an address area as well as a data word lengthof the packet and type information of the packet. The address area holdsaddress information about registers and a memory in the liquid crystaldriving control device 1. Data corresponding to the address informationand a command are held in a data area of the body part.

When the parallel interface circuit 3 is employed for an interface withthe host device, the address information, command, and data are receivedfrom a data input-output terminal DB0-7 via the packet.

On receiving a command packet from the host device, the host interfacecircuit 2 stores the address information in a command address register(CAREG) 10. A command address decoder (CADEC) 12 decodes a commandaddress stored in the command address register 10 to generate a registerselect signal and the like. Command data received by the packet issupplied to a command data register array (CORED) 11. The command dataregister array 11 has numerous command data registers mapped intopredetermined addresses, respectively. A command data register to storethe received command is selected by the register select signal outputtedfrom the command address decoder 12. The command data latched into thecommand data register is supplied to a corresponding circuit portion asan instruction or control data, and controls internal operations. Thecommand data register array 11 may be directly selected by the registerselect signal RS to set the command data in the command data register.

On receiving a data packet from the host device, the host interfacecircuit 2 supplies the address information to an address counter 13. Theaddress counter 13 performs an increment operation and the likeaccording to the contents of the corresponding command data register toperform addressing for a display memory (GRAM) 14. If an accessindication by the command data is a write operation on the displaymemory 14, data of the data packet is supplied to a write data register(WDR) 9 via a bus 15, and stored in the display memory (GRAM) 14 in anappropriate timing. Display data is stored in units of display frames.If an access indication by the command data is a read operation on thedisplay memory 14, data stored in the display memory is read into a readdata register (RDR) 16 and becomes ready to be supplied to the hostdevice. When the command data register receives a display command, aread operation synchronous with a display timing is performed for thedisplay memory 14. Timing control of reading and displaying is performedby a timing generator (TGNR) 17. Display data read from the displaymemory 14 synchronously with the display timing is latched into a latchcircuit (LAT) 18. The latched data is given to a source driver (SOCDRV)20. A liquid crystal display subject to driving control by the liquidcrystal driving control device 1 is constructed by a TFT (Thin FilmTransistor) liquid crystal panel of dot matrix type, and includesdriving terminals with numerous source electrodes as signal electrodesand numerous gate electrodes as scanning electrodes. The source driver(SOCDRV) 20 drives the source electrodes of the liquid crystal displayby a driving terminal S1-720. A driving level of the driving terminalS1-720 is determined using a gradation voltage generated in a gradationvoltage generating circuit (TWVG) 21. The gradation voltage is subjectedto gamma correction in a gamma correction circuit (γMD) 22. A scan datagenerating circuit (SCNDG) 24 generates scanning data synchronously withscanning timing from the timing generator 17. The scanning data issupplied to a gate driver (GTDRV) 25. The gate driver 25 drives the gateelectrodes of the liquid crystal display by a driving terminal G1-320. Adriving level of the driving terminal G1-320 is determined using adriving voltage generated in a liquid crystal driving level generatingcircuit (DRLG) 26.

A clock pulse generator (CPG) 28 inputs a source oscillation clock fromterminals OSC1 and OSC2 to generate an internal clock, and supplies itto the timing generator 17 as an operation timing reference clock. Aninternal reference voltage generating circuit (IVREFG) 29 generates areference voltage and supplies it to an internal logic power regulator(ILOGVG) 30. The internal logic power regulator 30 generates an internallogic power on the basis of the reference voltage.

<Endian Setting Circuit>

FIG. 3 shows signal lines for a parallel interface in the liquid crystaldriving control device. Signal lines 31 for connecting the liquidcrystal driving control device 1 and a host device 30 are signal linesfor a chip select signal CS, a write signal WR, a register select signalRS, and a data terminal DB7-0. The liquid crystal driving control device1 can select whether the parallel interface is to be used as a bigendian or little endian. As shown in FIG. 3, the big endian is a mode inwhich high-order bytes (Hbyt) and low-order bytes (Lbyt) of data aretransferred in that order. The little endian is a mode in whichlow-order bytes and high-order bytes of data are transferred in thatorder. The endian must be the same between a transfer master and atransfer slave.

FIG. 1 shows an example of an endian setting circuit in a parallelinterface circuit. An address area of a command packet has 16 bits, anda data area following the address area has 16 bits. Since the paralleldata input terminal DB7-0 has eight bits, a 16-bit command address inthe address area is inputted twice, eight bits at a time, and 16-bitcommand data in the data area following the address area is inputtedtwice, eight bits at a time. For a data latch (DLH) 32, its high-ordereight bits (IB15-8) are inputted. For a data latch (DLL) 33, itslow-order eight bits (IB7-0) are inputted. Output (IB15-0) of the datalatches 32 and 33 is organized into 16 bits and connected in parallel toan input terminal of the command address register 10 and input of thecommand data register array 11.

The command data register array 11 includes an endian setting register(ESREG) 35 for holding an endian setting command as control data forcontrolling whether the parallel interface with the outside is to beused as a big endian or a little endian. When the command addressregister 10 holds command address information for selecting the endiansetting register 35, the command address decoder 12 selects the endiansetting register (ESREG) 35. When a first endian setting command isloaded into the selected endian setting register 35, a control signalTCREV is set to a logical value 1. When a second endian setting commandis loaded into the selected endian setting register 35, the controlsignal TCREV is set to a logical value 0. The control signal TCREV issupplied to a switching circuit (CHG) 36. The switching circuitgenerates data fetch pulses (latch pulses) φLPH and φLPL of the datalatches 32 and 33. The data latch 32 latches input data synchronouslywith a change in the high-order latch pulse φLPH. The data latch 33latches input data synchronously with a change in the low-order latchpulse φLPL. When the control signal TCREV is the logical value 1, theswitching circuit 36 changes the low-order latch pulse φLPLsynchronously with a pulse change in a first transfer pulse φTPF changedsynchronously with transfer of low-order byte data of 16-bit data.Likewise, the switching circuit 36 changes the high-order latch pulseφLPH synchronously with a pulse change in a second transfer pulse φTPSchanged synchronously with transfer of high-order byte data of 16-bitdata. On the other hand, when the control signal TCREV is the logicalvalue 0, the switching circuit 36 changes the high-order latch pulseφLPH synchronously with a pulse change in the first transfer pulse φTPFchanged synchronously with transfer of low-order byte data of 16-bitdata. Likewise, the switching circuit 36 changes the low-order latchpulse φLPL synchronously with a pulse change in the second transferpulse φTPS changed synchronously with transfer of high-order byte dataof 16-bit data. A transfer counter (TCUNT) 37 counts cyclically counts 0or 1 for each write cycle by a write signal in a state in which a chipis selected by the signal CS. At odd-numbered write cycles, the countvalue 0 is outputted. At even-numbered write cycles, the count value 1is outputted. A decoder (DEC) 38 decodes the count value, and changesthe first transfer pulse φTPF at odd-numbered write cycles and the firsttransfer pulse φTPF at even-numbered write cycles.

FIG. 4 shows operation timing of the endian setting circuit of FIG. 1.The switching circuit 36 regards the parallel interface as the littleendian when the control signal TCREV is the logical value 1, and whenthe control signal TCREV is the logical value 0, regards the parallelinterface as the big endian. FIG. 5 concisely shows an operation mode ofthe switching circuit 36.

FIG. 6 shows command address information CMDAS for selecting the endiansetting register 35, a first endian setting command CMDDL, and a secondendian setting command CMDDB. The command address information is h0606.In short, as shown in FIG. 7 that shows an address map of the commanddata register, the endian setting register (ESREG) 35 is mapped at anaddress h0606. As shown in FIG. 6, the first endian setting commandCMDDL is h0101. The second endian setting command CMDDB is h0000. InFIG. 6, a value TV in the positions of bit 0 (IB0) and bit 8 (IB8) is 1for the first endian setting command CMDDL, and 0 for the second endiansetting command CMDDB. The values of other bits IB1 to IB7, and IB9 toIB15 are 0. The above-described values h0606, h0101, and h0000 areexamples of information with unchanged values in specific bit positionseven if high-order and low-order bit positions are transposed.Therefore, when the host device 30 sets an endian immediately after thehost device 30 releases the reset, if the host device 30 uses the littleendian, it has only to issue the first endian setting command CMDDLalong with the command address information CMDAS to the liquid crystaldriving control device 1. If the host device 30 uses the big endian, ithas only to issue the second endian setting command CMDDB along with thecommand address information CMDAS to the liquid crystal driving controldevice 1. Whatever the initial status of endian setting in the liquidcrystal driving control device, the endian of the liquid crystal drivingcontrol device does not need to be recognized at all. This is becausethe values h0606, h0101, and h0000 are identical even if high-order andlow-order bit positions are transposed.

The signal TCREV is a signal indicating a logical product of the value(TV) of the bit IB0 and the value (TV) of the bit IB1. It is verified bythe signal TCREV that both the values of the bits IB0 and IB1 are 1 forthe endian setting command CMDDL. A logic of verifying whether the valueof each bit of the endian setting command is correct may be employed togenerate the signal TCREV, but is not used here. The reasons follow.That is, the endian setting register (ESREG) 35 must be specified with acorrect address h0606 supplied. An initial status by power-on reset isbig endian setting (TCREV=0), and for a command for changing to littleendian setting, IB0 and IB1 of the value h0101 can be correctlyverified. As long as operations based on the command specifications ofFIG. 6 are performed, normal endian control is guaranteed. For thesereasons, for the logic of generating the signal TCREV, even if thevalues of bits IB1 to IB7, and IB9 to IB15 are not cared, and any one ofIB0 and IB8 is 1 for resetting from the little endian to the big endian,there is no serious trouble. This remarkably simplifies the logic ofdetermining the endian setting command.

<Cellular Phone>

FIG. 8 shows a cellular phone (CPHN) 41 relating to a data processingsystem to which the liquid crystal driving control device 1 is applied.A receive signal of a radio band received by an antenna 42 is sent to ahigh-frequency interface part (RFIF) 43. The receive signal is convertedinto a signal of a low frequency, decoded, and converted into a digitalsignal by the high-frequency interface part 43, and supplied to abaseband part (BBP) 44. The baseband part 44 performs channel codecprocessing using a microcomputer (MCU) 45 and the like, releases thesecrecy of the received digital signal, and performs error correction.The baseband part 44 uses an application specific semiconductor device(ASIC) 46 to perform division into control data necessary forcommunications and compressed voice data. The control data is sent tothe MCU 45, which performs communication protocol processing. The voicedata extracted in the channel codec processing is decompressed using theMCU 45, supplied to a voice interface circuit (VCIF) 49 as voice data,converted into an analog signal, and reproduced as voice by aloudspeaker 47. In the case of transmission operations, a voice signalinputted from a microphone 48 is converted into a digital signal in thevoice interface circuit 49, subjected to filter processing using the MCU45 and the like, and converted into compressed voice data. The ASIC 46synthesizes the compressed voice data and the control data from the MCU45 into a train of transmission data, and adds error correction anddetection code and secret code to the train of transmission data byusing the MCU 45 to produce transmission data. The transmission data isconverted in the high-frequency interface part 43, and the convertedtransmission data is converted into a signal of a high frequency andsent out as a radio signal from the antenna 42.

The MCU 45 issues display commands and display data to the liquidcrystal driving control device (LCDCNT) 1. In response, the liquidcrystal driving control device (LCDCNT) 1 displays an image on a liquidcrystal display 50. The MCU 45 includes circuit units such as a centralprocessing unit (CPU) and a digital signal processing processor (DSP).The MCU 45 may be constructed separately to a baseband processor (BBP)exclusively responsible for baseband processing for communications, andan application processor (APP) exclusively responsible for extrafunction control such as display control and security control. TheLCDCNT 1, ASIC 46, and MCU 45 are respectively constructed by specificsemiconductor devices although there is no particular limitation. Inthis embodiment, the MCU 45 is used as a host device of the liquidcrystal driving control device 1. As an interface between the MCU 45 andthe liquid crystal driving control device 1, a parallel interface by thesignal lines 321 is selected.

FIG. 9 shows an example of endian setting operations by the MCU 45. TheMCU 45 functions as a transfer master that performs the parallelinterface in a little endian mode. The liquid crystal driving controldevice 1 is initialized so that the parallel interface is performed inthe little endian mode by a power-on reset.

The MCU 45 performs processings S1 and S2 immediately after the power-onreset is released. In processing S1, the MCU 45 issues a command addressh0606. Although the endians of the MCU 45 and the LCDCNT 1 are differentfrom each other, even if the high-order and low-order bit positions ofthe command address h0606 are transposed, since the value of the commandaddress h0606 is the same, the endian setting command register 35 isnormally selected. In processing S2, the MCU 45, to match the endian ofthe LCDCNT 1 to its own endian, issues a first endian setting commandCMDDL of a value h0101 to specify the little endian. Although theendians of the MCU 45 and the LCDCNT 1 are still different from eachother, even if the high-order and low-order bit positions of the commanddata h0101 are transposed, since the value of the command data h0101 isthe same, the command data H0101 is normally set in the endian settingcommand register 35. Thereby, the endian of the LCDCNT 1 is changed fromthe big endian to the little endian. In processing S3 after that, sinceboth the MCU 45 and the LCDCNT 1 operate in the little endian, anycommand addresses and any command data can be normally processed.

Although not shown, when the endian of the MCU 45 is the big endian,immediately after the power-on reset, the MCU 45 has only to issue thecommand address h0606 and a second endian setting command CMDDB of thevalue h0000.

FIG. 10 is a drawing for explaining the operation of dynamicallyswitching endian settings when both a baseband processor (BBP) 45A andan application processor (APP) 45B control the liquid crystal drivingcontrol device (LCDCNT) 1 as host devices. The BBP 45A functions as atransfer master that performs the parallel interface in a little endianmode. The liquid crystal driving control device 1 is initialized so thatthe parallel interface is performed in the big endian mode by a power-onreset. As shown in FIG. 10, when the BBP 45A controls the LCDCNT 1, ituses an endian setting command so that the LCDCNT 1 can operate in thelittle endian mode. An example of this is the case where a clock isdisplayed on a liquid crystal display using a real time clock of the BBP45AQ in a standby state of a cellular phone. When the APP 45B controlsthe LCDCNT 1, it uses an endian setting command so that the LCDCNT 1 canoperate in the big endian mode. By the endian switching function of theLCDCNT 1, it is possible to dynamically switch endians.

Hereinbefore, though the invention made by the inventors of the presentinvention has been described in detail based on the preferredembodiments, it goes without saying that the present invention is notlimited to the preferred embodiments, but may be modified in variousways without changing the main purports of the present invention.

For example, in this specification, commands denote not onlyinstructions set in a command register, but also control data to be setin control registers such as a port control register. In short, in thecase of a liquid crystal driving control device, data other than displaydata is commands, and denote instruction data that commands an operationin some sense. A construction which allows a serial interface to beselected as a host interface in one liquid crystal driving controldevice is not mandatory to the present invention. A host device is notlimited to one MCU 45 used for baseband processing and applicationprocessing. The host device may be a baseband processor and/or anapplication processor, or may be other circuits.

Address information endian setting is not limited to h0606 Likewise,endian setting commands are not limited to h0000 and h0101. Even ifhigh-order and low-order bit positions are transposed, there is noproblem if the values of specific bit positions are unchanged. Thevalues of high-order bits and low-order bits do not necessarily need tobe identical with each other. The high-order bit positions or thelow-order bit positions of data are not limited to be byte units. Theymay be word units or long word units.

The present invention, without being limited to cellular phones, can bewidely applied to portable data processing terminals such as PDA(personal digital assistant), and various data processing systems suchas storage terminals. Semiconductor devices or peripheral devices arenot limited to liquid crystal driving control devices. The presentinvention can be applied to various circuits and devices such as graphiccontrollers, memory controllers, bus controllers, direct memory accesscontrollers, and memories.

What is claimed is:
 1. A semiconductor device including a processingunit and a plurality of data terminals, the processing unit comprising:an interface circuit configured to receive an endian setting commandfrom the plurality of data terminals; and an endian setting registerconfigured to store the endian setting command, wherein the interfacecircuit is configured to switch operation between a big endian mode anda little endian mode based on a value of the endian setting commandstored in the endian setting register, wherein the endian settingcommand is comprised of a high-order bit portion and a low-order bitportion, and wherein the high-order bit portion and the low-order bitportion of the endian setting command are identical.
 2. A semiconductordevice according to claim 1, further comprising: a data bus configuredto transfer the endian setting command from the interface circuit to theendian setting register, wherein the bit length of each of thehigh-order bit portion and the low-order bit portion of the endiansetting command is a same as the width of the data bus.
 3. Asemiconductor device according to claim 2, further comprising: a gatedriver circuit and a source driver circuit configured to output displaydata to a liquid crystal display panel.
 4. A semiconductor deviceincluding a processing unit and a plurality of data terminals, theprocessing unit comprising: an interface circuit configured to receivean endian setting command and an endian setting address from theplurality of data terminals; and an endian setting registercorresponding to the endian setting address and configured to store theendian setting command, wherein the interface circuit is configured toswitch operation between a big endian mode and a little endian modebased on a value of the endian setting command stored in the endiansetting register, wherein each of the endian setting command and theendian setting address is comprised of a high-order bit portion and alow-order bit portion, wherein the high-order bit portion and thelow-order bit portion of the endian setting command are identical, andwherein the high-order bit portion and the low-order bit portion of theendian setting address are identical.
 5. A semiconductor deviceaccording to claim 4, further comprising: a data bus configured totransfer the endian setting command from the interface circuit to theendian setting register, wherein the bit length of each of thehigh-order bit portion and the low-order bit portion of the endiansetting command is a same as the width of the data bus of the processingunit, and wherein the bit length of each of the high-order bit portionand the low-order bit portion of the endian setting address is a same asthe width of the data bus of the processing unit.
 6. A semiconductordevice according to claim 5, further comprising: a gate driver circuitand a source driver circuit configured to output display data to aliquid crystal display panel.
 7. A semiconductor device including aprocessing unit and a data input, the processing unit comprising: aninterface circuit configured to receive an endian setting command and anendian setting address from the data input; and an endian settingregister configured to store the endian setting command, wherein theinterface circuit is configured to switch operation between a big endianmode and a little endian mode based on a value of the endian settingcommand stored in the endian setting register, wherein the endiansetting command is comprised of a high-order bit portion and a low-orderbit portion, and wherein the high-order bit portion and the low-orderbit portion of the endian setting command are identical.
 8. Asemiconductor device according to claim 7, further comprising: a databus configured to transfer the endian setting command from the interfacecircuit to the endian setting register, wherein the bit length of eachof the high-order bit portion and the low-order bit portion of theendian setting command is a same as the width of the data bus.
 9. Asemiconductor device according to claim 8, further comprising: a gatedriver circuit and a source driver circuit configured to output displaydata to a liquid crystal display panel.
 10. A semiconductor deviceincluding a processing unit and a data input, the processing unitcomprising: an interface circuit configured to receive an endian settingcommand and an endian setting address from the data input; and an endiansetting register corresponding to the endian setting address andconfigured to store the endian setting command, wherein the interfacecircuit is configured to switch operation between a big endian mode anda little endian mode based on a value of the endian setting commandstored in the endian setting register, wherein each of the endiansetting command and the endian setting address is comprised of ahigh-order bit portion and a low-order bit portion, wherein thehigh-order bit portion and the low-order bit portion of the endiansetting command are identical, and wherein the high-order bit portionand the low-order bit portion of the endian setting address areidentical.
 11. A semiconductor device according to claim 10, furthercomprising: a data bus configured to transfer the endian setting commandfrom the interface circuit to the endian setting register, wherein thebit length of each of the high-order bit portion and the low-order bitportion of the endian setting command is a same as the width of the databus, and wherein the bit length of each of the high-order bit portionand the low-order bit portion of the endian setting address is a same asthe width of the data bus of the display driver.
 12. A semiconductordevice according to claim 11, further comprising: a gate driver circuitand a source driver circuit configured to output display data to aliquid crystal display panel.